We propose to complete the construction and installation of instrumentation to make available a dedicated laser-driven flash x-ray source for qualified users to perform a variety of structural kinetic studies. Using instrumentation acquired during the past year, we have demonstrated the ability to produce single shot, subnanosecond exposure x-ray diffraction patterns from typical biological membrane systems, including dried rat spinal roots, and purple membranes of the Halobacterium halobium. Successful demonstration of this capability required the use of a very large, multi-stage Nd:glass laser system which has been constructed as part of the National Laser User Facility at the University of Rochester's Laboratory for Laser Energetics. The instrumentation being assembled under the present grant is dedicated to the quantitative detection and processing of these diffraction patterns and to convenient operation of this facility for users. The investigators are planning to use the facility to study the time course of conformational changes in photostimulated membrane systems such as purple membrane.